This is the Spektrum RC S904 Large Scale Water Proof Digital Servo.
Specifications:
Product Length: 2.33 in (59.1mm)
Product Width: 1.14 in (29mm)
Servo Operating Voltage: 6.0V
Product Height: 2.16 inch (54.9mm)
Servo Type: Digital
Maximum Servo Torque: 496 oz-in
Spektrum RC
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